The computation of the genus of curves over the field with 2 elements
raises an error message for some small curves. I'm using a selfcompiled
Sage 5.8 on a 64 bit linux system:
{
sage: k.<x,y>=GF(2)[]
sage: f=y^10 + x^7 + x^3
sage: c=Curve(f)
sage: print c.genus()
---------------------------------------------------------------------------
RuntimeError Traceback (most recent call last)
<ipython-input-4-42d6d43d4414> in <module>()
----> 1 print c.genus()
/home/mueller/local/sage-5.8/local/lib/python2.7/site-packages/sage/schemes/plane_curves/curve.pyc
in genus(self)
98 The geometric genus of the curve.
99 """
--> 100 return self.geometric_genus()
101
102 def geometric_genus(self):
/home/mueller/local/sage-5.8/local/lib/python2.7/site-packages/sage/schemes/plane_curves/curve.pyc
in geometric_genus(self)
139 return self.__genus
140 except AttributeError:
--> 141 self.__genus = self.defining_ideal().genus()
142 return self.__genus
143
/home/mueller/local/sage-5.8/local/lib/python2.7/site-packages/sage/rings/polynomial/multi_polynomial_ideal.pyc
in __call__(self, *args, **kwds)
600 if not R.base_ring().is_field():
601 raise ValueError("Coefficient ring must be a field for
function '%s'."%(self.f.__name__))
--> 602 return self.f(self._instance, *args, **kwds)
603
604 require_field = RequireField
/home/mueller/local/sage-5.8/local/lib/python2.7/site-packages/sage/rings/polynomial/multi_polynomial_ideal.pyc
in genus(self)
1743 import sage.libs.singular
1744 genus = sage.libs.singular.ff.normal__lib.genus
-> 1745 self.__genus = Integer(genus(self))
1746 return self.__genus
1747
/home/mueller/local/sage-5.8/local/lib/python2.7/site-packages/sage/libs/singular/function.so
in sage.libs.singular.function.SingularFunction.__call__
(sage/libs/singular/function.cpp:12288)()
/home/mueller/local/sage-5.8/local/lib/python2.7/site-packages/sage/libs/singular/function.so
in sage.libs.singular.function.call_function
(sage/libs/singular/function.cpp:13841)()
RuntimeError: Error in Singular function call 'genus':
delta not found, please inform the authors
leaving normal.lib::deltaP
leaving normal.lib::genus
}
--
You received this message because you are subscribed to the Google Groups
"sage-support" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-support?hl=en.
For more options, visit https://groups.google.com/groups/opt_out.
